<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		<div id="show">还剩5秒</div>
		<script>
			window.onload=function(){
				var showdiv=document.getElementById('show')
				var timer=5;
				setInterval(function(){
					timer=timer-1;
					showdiv.innerHTML="还剩"+timer+"秒";
					if(timer==0){
						window.close();
					}
				},1000)
			}
		</script>
	</body>
</html>